Synthesis of 3,4,5-Trisubstituted-1,2,4-triazoles

A study was conduct to investigate the synthesis of 3,4,5-trisubstituted-1, 2,4-triazoles. It was demonstrated that several types of intermediates were used to synthesize target compounds, such as N-acylamidrazones, dichloroaldazines, and triazolopyrazines. N-acylamidrazone intermediates were found to be most common intermediates used to synthesize 3,4,5-trisubstituted 1,2,4-triazoles are N-acylamidrazones. Several precursors, such as activated amide derivatives, amidrazones, N'-acetyl-N,N-dimethylhydrazonamides, oxadiazoles,N- nitrosoamidines, and orarylphosphazoanilides led to N-acylamidrazones. The use of activated amide derivatives was one of the most common general methods leading to N-acylamidrazones. N-acylamidrazones were obtained by condensation of chloromethylene amides with hydrazides, while different types of protected hydrazine were used to access more complex N-protected hydrazides.